A high-salt phosphate-functionalized silicide material for efficient uranium extraction with ultra-low feed amount and a preparation method thereof

Abstract

The invention discloses a method for preparing a high-salt phosphate-functionalized silicide material for efficient uranium extraction with ultra-low feed amount, comprising mixing phytic acid, ethanol and water in a certain proportion, adding vinyl triethoxysilane, stirring evenly, heating and reacting, naturally cooling to room temperature, centrifuging to obtain a precipitate, washing, and vacuum drying to obtain a phosphate-functionalized silicide material. The process is simple and easy, the synthesis conditions are mild, and the phosphate-functionalized silicide material prepared by the method of the invention has a fast uranium adsorption rate and excellent salt resistance at an ultra-low feed amount of 0.06 g / L.

Description

Technical Field

[0001] The present invention relates to the field of novel functional materials, and in particular to a high-salt resistant phosphoric acid functionalized silicide material for efficient uranium extraction with ultra-low feed amount and a preparation method thereof. Background Art

[0002] Nuclear energy has the advantages of high energy density, stable energy supply and low carbon emissions, and is an economically viable energy source. However, the large amount of uranium-containing wastewater generated by the nuclear industry seriously threatens human health and ecological and environmental safety. Therefore, the efficient separation and recovery of uranium in uranium-containing wastewater is crucial to the sustainable development of the nuclear industry, human health and ecological and environmental safety. In addition, the wastewater generated by the nuclear industry usually contains some salts that hinder the removal of uranium, such as sodium chloride and sodium nitrate. Therefore, it is a challenging task to efficiently remove uranium pollutants from high-salt wastewater.

[0003] Existing uranium removal methods mainly include ion exchange, liquid-liquid extraction, coprecipitation, redox, evaporation, membrane filtration and solid phase adsorption. Among them, solid phase adsorption has been widely studied due to its economic, efficient and simple characteristics. However, many adsorbents such as carbon materials, zeolites, montmorillonites, etc. are usually strongly interfered by high salt, which limits their practical application. At present, there are literature reports that silicide materials such as silicon flakes, mesoporous silica, Fe3O4@SiO2 and magnesium silicate flakes are used to remove and recover uranium pollutants in high-salt environments. However, most silicide materials have a slow adsorption rate on the one hand, which is difficult to meet the needs of rapid removal of uranium pollutants; on the other hand, the amount of adsorbent material is large, resulting in high cost. Therefore, it is very necessary to develop high-salt resistant silicide materials that can quickly and efficiently extract uranium pollutants at low feed rates. Summary of the invention

[0004] In view of this, the present invention provides a new type of uranium extraction material to solve the problems of slow adsorption speed, relatively poor salt resistance and large feed amount in existing uranium adsorption materials.

[0005] On one hand, the present invention provides a method for preparing a high-salt phosphate-functionalized silicide material for efficient uranium extraction with ultra-low feed amount, comprising the following steps: mixing phytic acid, ethanol and water in a certain proportion, adding vinyl triethoxysilane, stirring until mixed, heating to react, then naturally cooling to room temperature, centrifuging to obtain a precipitate, washing it, and vacuum drying to obtain the phosphate-functionalized silicide material.

[0006] Preferably, the amount of phytic acid added is 4 mmol, and the amount of vinyltriethoxysilane added is 5 mL.

[0007] Preferably, the amount of ethanol used is 30 mL, and the amount of water used is 5 mL.

[0008] Preferably, the heating reaction is carried out at 60° C. for 2 h.

[0009] The method for preparing a phosphoric acid functionalized silicide material for extracting uranium from high-salt wastewater provided by the present invention has a simple process flow and mild synthesis conditions. Furthermore, the phosphoric acid functionalized silicide material prepared by the method of the present invention is characterized by ICP-OES elemental analysis results and FT-IR spectrum characterization analysis results to infer its grafting mode as follows Figure 1 , the P / Si atomic ratio of VTES-PA4 is 6.06, and the material has functional groups such as P-OH, P=O, Si-OH, Si-O-Si, and C=C. Its special structure determines that the phosphoric acid functionalized silicide material has a fast uranium adsorption rate and excellent salt resistance at an ultra-low feed amount of 0.06g / L. Not only does it reach uranium adsorption equilibrium within 7 minutes in a 12ppm uranium solution, and the uranium removal rate reaches 97.4%; it also shows strong salt resistance in high-salt uranium-containing wastewater containing 5M NaCl and NaNO3, respectively, with uranium removal rates reaching 76.9% and 86.6%, respectively. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 Schematic diagram of the preparation of the high-salt phosphate-resistant functionalized silicide material VTES-PA4 of the present invention;

[0011] Figure 2 This is the infrared characterization spectrum of the high-salt phosphate-resistant silicide material VTES-PA4;

[0012] Figure 3 The morphology of the high-salt phosphate-resistant functionalized silicide material VTES-PA4, where a represents the SEM image and b represents the TEM image;

[0013] Figure 4 The water drop contact angle test results of high-salt phosphate-resistant silicide materials VTES-PA4, VTES-PA6 and VTES-PA8 are shown respectively;

[0014] Figure 5 Schematic diagram of uranium adsorption kinetics of high-salt phosphate-functionalized silicide materials VTES-PA4, VTES-PA6 and VTES-PA8;

[0015] Figure 6 Schematic diagram of the test results of uranium extraction performance of high-salinity phosphate-functionalized silicide material VTES-PA4 in high-salinity uranium-containing wastewater with different salinities. DETAILED DESCRIPTION

[0016] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0017] Example 1: Reference Figure 1 A method for preparing a high-salt phosphate-functionalized silicide material for efficient uranium extraction with ultra-low feed amount, comprising the following steps: 4 mmol phytic acid (PA), 30 mL ethanol and 5 mL ultrapure water are mixed together, and then 5 mL vinyl triethoxysilane (VTES) is added and stirred until mixed; then, the mixture is heated and stirred at 60°C for 2 h, and then naturally cooled to room temperature; a precipitate is obtained by centrifugation and washed with ethanol; and the washed product is vacuum dried at 45°C to obtain a white powder (VTES-PA4).

[0018] Comparative Example 1: The difference between Comparative Examples 1 and 2 and Example 1 is that the amounts of phytic acid used are different. The amounts of phytic acid in Comparative Examples 1 and 2 are 6 mmol and 8 mmol, respectively, and the obtained products are named VTES-PA6 and VTES-PA8, respectively.

[0019] The phosphoric acid functionalized silicide material prepared in Example 1 was characterized and its performance tested, and the results are as follows:

[0020] 1. Phosphoric acid functionalized silicide was characterized by Fourier transform infrared spectroscopy (FT-IR). Figure 2 As shown, the VTES-PA4 product shows the following characteristic absorption peaks: 1067 cm -1 (P-OH), 1170cm -1 (P=O), 3160-3700cm -1 (OH), 966cm -1 (Si-OH), 1123 cm -1 (Si-O-Si), 1640cm -1 (C=C), indicating the successful synthesis of phosphoric acid functionalized silicide material.

[0021] 2. VTES-PA4 was characterized using field emission scanning electron microscopy (SEM). The results are as follows: Figure 3 As shown in a, the microscopic morphology of VTES-PA4 presents a uniform coral-like shape. In addition, VTES-PA4 was further characterized using transmission electron microscopy (TEM). Figure 3 (b) TEM image of VTES-PA4 shows a porous nanostructure, which is beneficial for the transport of metal cations in water.

[0022] 3. The hydrophilicity of phosphoric acid functionalized silicide was tested using a water drop contact angle test. The results are as follows: Figure 4As shown, as the content of phytic acid added during material synthesis decreased from 8 mmol to 4 mmol, it was found that the water droplet contact angle of the obtained phosphoric acid functionalized silicide gradually decreased. The smaller water droplet contact angle (14.8°) indicated that VTES-PA4 had the most excellent hydrophilicity, which was beneficial to the adsorption of uranyl ions.

[0023] 4. The VTES-PA4 prepared in Example 1, and the VTES-PA6 and VTES-PA8 prepared in Comparative Examples 1 and 2 were tested for uranium extraction performance in uranium-containing wastewater. As shown in Table 1, as the amount of phytic acid input decreased from 8 mmol to 4 mmol, it was unexpectedly found that the ratio of P to Si atoms in the obtained phosphoric acid functionalized silicide (obtained by ICP-OES elemental analysis test) gradually increased, and its uranium removal rate in a 12 ppm uranium solution increased. Figure 5 As shown in the schematic diagram of uranium adsorption kinetics, at a temperature of 308.15K, using an ultra-low feed amount of 0.06 g / L, in a 12 ppm uranium solution with a pH of 4.5, VTES-PA4 reaches uranium adsorption equilibrium within 7 minutes, and the uranium removal rate is as high as 97.4%.

[0024] Table 1 Effect of different amounts of phytic acid on the structure and uranium extraction performance of phosphoric acid functionalized silicide

[0025]

[0026] 5. The VTES-PA4 prepared in Example 1 was tested for its uranium extraction performance in high-salinity uranium-containing wastewater with different salinities. The results are as follows: Figure 6 It is shown that at a temperature of 308.15K, using an ultra-low feed amount of 0.06g / L VTES-PA4, in a high-salt 12ppm uranium-containing wastewater containing 5M NaCl and NaNO3 at pH = 4.5, VTES-PA4 exhibits strong salt resistance, and the uranium removal rates reach 76.9% and 86.6%, respectively. At the same time, compared with the existing phosphoric acid functionalized similar materials, the salt resistance of the VTES-PA4 of the present invention is better than most other materials for extracting uranium from high-salt uranium-containing wastewater at a low dose, as shown in Table 2.

[0027] Table 2 Comparison of uranium adsorption capacity of VTES-PA4 and previously reported adsorbents under high salt conditions

[0028]

[0029] Note: The a value is estimated from the literature data chart, and the b value is calculated from the a value, uranium concentration and adsorbent dosage.

[0030] Document 1: Thermal-responsive ion-imprinted magnetic microspheres for selective separation and controllable release of uranium from highly salineradioactive effluents, Sep.Purif.Technol.246(2020)116917.

[0031] Document 2: Interlayer spacing adjusted zirconium phosphate with 2D ionchannels for highly efficient removal of uranium contamination in radioactiveeffluent, Chem.Eng.J.429(2022)132265.

[0032] In summary, the method for preparing a phosphoric acid functionalized silicide material for extracting uranium from high-salt wastewater provided by the present invention has a simple and easy process flow and mild synthesis conditions. The phosphoric acid functionalized silicide material with the best performance obtained by the present invention has a fast uranium adsorption rate and excellent salt resistance at an ultra-low feed amount of 0.06g / L. In a 12ppm uranium solution, uranium adsorption equilibrium is reached within 7min, and strong salt resistance is shown in ultra-high-salt uranium-containing wastewater containing 5M NaCl and NaNO3, and the uranium removal rates reach 76.9% and 86.6% respectively.

[0033] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a high-salt phosphate-functionalized silicide material for high-efficiency uranium extraction with ultra-low feed amount, characterized in that The following steps are involved: After phytic acid, ethanol and water are mixed in a certain proportion, vinyl triethoxysilane is added and stirred until the mixture is uniform, and then heated for reaction, and then naturally cooled to room temperature. The precipitate is obtained by centrifugation and washed, and vacuum dried to obtain a phosphoric acid functionalized silicide material. The phytic acid input amount is 4 mmol, the vinyl triethoxysilane input amount is 5 mL, the ethanol input amount is 30 mL, and the water input amount is 5 mL.

2. The method for preparing a high-salt phosphate-resistant functionalized silicide material for high-efficiency uranium extraction with ultra-low feed amount according to claim 1, characterized in that: The heating reaction is carried out at 60° C. for 2 h.

3. A high-salt phosphate-resistant functionalized silicide material for efficient uranium extraction with ultra-low feed amount prepared according to the method of claim 1 or 2.

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